The present embodiments relate to a holding arm and an arrangement with the holding arm provided for a radiation therapy device.
The use of radiation to destroy diseased tissue (e.g., a tumor) is a widely used procedure in therapeutic medicine. Systems that use high-energy electromagnetic radiation may be employed. Such a system is described by way of example in U.S. Pat. No. 6,839,404 B2.
During the course of radiation therapy, it may be desirable to use the same device to perform diagnostic irradiation. This may be used to monitor and better locate the tumor to be irradiated around the time of or during therapeutic irradiation. In the abovementioned publication, radiation therapy is provided with a Portal Imaging System for this purpose. This system allows “in-line” imaging. The radiation generated by the therapy device for tissue treatment (e.g., MV radiation generated using a linear accelerator) is also used for diagnostic purposes and is detected using a detector after penetrating the object. This allows therapeutic and diagnostic radiation to be supplied in an essentially parallel manner and from the same source, which represents a significant simplification. The source may be adapted for low-energy radiation (e.g., kV range) by using, for example, a carbon target instead of a tungsten target. This procedure is also described in the publication “In-Line kView Imaging” by Siemens AG.
According to a development of the “in-line” concept, an antiparallel rather than a parallel diagnostic beam is used. A beam source replaces the detector. Additionally, a detector for the diagnostic radiation is disposed in a region of an exit point of the therapeutic radiation for the diagnostic application. This detector for diagnostic irradiation, which is positioned in the beam path of the therapeutic radiation, is removed for therapeutic irradiation (e.g., folded back). This procedure with a separate beam source allows the diagnosis to be performed with a lower dose (e.g., kV range), without the therapeutic beam source having to be adapted for low-energy radiation. Both procedures (e.g., parallel and antiparallel irradiation) have the advantage that the system as a whole is not rotated for the recordings to switch between the positions for therapeutic and diagnostic radiation.
Radiation therapy systems, as shown, for example, in FIG. 1 and FIG. 2, may have only one degree of freedom (e.g., rotation of the system as a whole). The irradiation device, therefore, is aligned with an isocenter (e.g., a tumor position) by positioning the patient table, for example. Positioning using the patient table is not ideal, primarily because positioning using the patient table is troublesome for the patient on the table, who may be in physically poor shape. Also, the system shown in FIG. 1 and FIG. 2 allows a tumor to be irradiated from different directions in a limited fashion.